Definitions for "Ponderous"
Very heavy; weighty; as, a ponderous shield; a ponderous load; the ponderous elephant.
Heavy; dull; wanting; lightless or spirit; as, a ponderous style; a ponderous joke.
slow and laborious because of weight; "the heavy tread of tired troops"; "moved with a lumbering sag-bellied trot"; "ponderous prehistoric beasts"; "a ponderous yawn"
having great mass and weight and unwieldiness; "a ponderous stone"; "a ponderous burden"; "ponderous weapons"
Important; momentous; forcible.
Keywords:  slower, lighter, slowly, faster, planet
A planet that is moving slowly is said to be ponderous. The slower of two planets is more ponderous than the faster one. The more ponderous planet receives an aspect; the lighter (faster) planet casts one.